JPH0394432A - Manufacture of resin-sealed electronic component - Google Patents

Abstract

PURPOSE:To manufacture this component of a good moldability by a method wherein a flow-suppressing member is arranged on the side of a resin injection port away from an electronic element and a flow of a resin for sealing use injected to one main face side of a support sheet from the resin injection port is suppressed CONSTITUTION:A semiconductor element 11 and a flow-stopping member, i.e., a flow-suppressing member 12, are fixed and bonded to one main face of a support sheet 2. The flow-suppressing member 12 is a rod-shaped metal body; it is extended in a width direction of the support sheet, i.e., in a direction perpendicular to an extension direction of an outer lead 3, and is arranged on the other end part side of the support sheet 2 away from the semiconductor element 11. Consequently, a resin 26 for sealing use injected from a resin injection port 23 flows after it has been branched to both one main face side and the other main face side of the support sheet 2; a flow of the resin 26 for sealing use injected into one main face side of the support sheet 2 is suppressed by the flow-suppressing member 12 which has been mounted on one main face of the support sheet 2. Thereby, a flow-suppressing effect can be adjusted without changing the shape of a lead frame whose handling property is good.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a resin-sealed hook part. The present invention relates to a method for manufacturing resin-consistent electronic components.

[Prior art and problems to be solved by the invention] A semiconductor element is fixed to one main surface of a support plate that also serves as a heat sink,
Among the semiconductor devices in which the support plate is covered with a resin sealant, there is a semiconductor device in which a portion of the resin sealant is also formed on the other main surface side of the support plate. This type of semiconductor device has the advantage of not requiring an insulating member such as a mica plate when attached to an external heat sink. However, in terms of heat dissipation, this is disadvantageous compared to a type of semiconductor device in which the back surface of the support plate is exposed. Therefore, it is necessary to reduce the thickness of the resin layer formed on the other main surface side of the support plate to about 0.5 to 1.0 mm to improve heat dissipation as much as possible. In order to form a thin resin layer on the lower side of the support plate, the support plate must be placed at a narrow distance from the bottom of the molding cavity, and the sealing resin must be injected into this narrow distance. For this reason,
In some cases, the sealing resin was not injected well, resulting in molding defects.

In order to solve the above problem, the applicant of the present application
No. 57,529 discloses a method 7 in which a convex portion is provided on the upper die of the molding die, and the convex portion suppresses the flow of the sealing resin on one main surface side of the support plate for resin molding. According to this resin molding method, the flow of the sealing resin on the other main surface side of the support plate can be relatively strengthened. For this reason, the balance between the amount of sealing resin injected into the main surface of the support plate and the amount of sealing resin injected into the other main surface of the support plate is improved, making it possible to compare resin molding. Can be done accurately. However, if the size or thickness of the support plate is changed, or if semiconductor elements and circuit boards are placed on the support plate one after the other, the injection balance of the resin for retaining records may become delicate. It has changed.

Therefore, in order to form different types of semiconductor devices, it is necessary to prepare corresponding molding molds for each type of semiconductor device, even if the shape of the resin molded body is the same. As a result, multiple expensive molds are required. Keita, IP! Japanese Patent Publication No. 1987-175433 discloses a method of resin molding by bending the support plate upward from the tip side thereof and suppressing the flow of the sealing resin to the upper surface of the support plate at this bent portion. ing. According to this resin molding method, it is thought that moldability can be improved by changing the height of the bent portion without changing the expensive mold design. However, the tip of the support plate in! Does bending the lead frame excessively complicate the lead frame processing process and increase costs? invite Furthermore, the ease of handling the lead frame is also reduced.

Therefore, an object of the present invention is to provide a method for manufacturing resin-sealed electronic components that solves the above problems. do.

[A thousand steps to solve problems]

To achieve the above object (1), the present invention comprises a first step of preparing a lead frame having a support plate and an external lead connected to one end K of the support plate; An electronic element is fixed to one main surface, and a longitudinal flow suppressing member extending in a direction perpendicular to the extending direction of the external lead is attached between the fixed position of the electronic element and the other end of the support plate. a second step of obtaining a lead frame assembly by fixing between the support plate and the bottom surface of the molding cavity; a third step of arranging the lead frame assembly in a mold such that the lead frame assembly is smaller than the distance from the top surface; and a resin injection port disposed on the other end side of the support plate in the molding cavity. injecting a sealing resin into the molding cavity, and suppressing the flow of the sealing resin injected onto one main surface side of the support plate in the molding cavity with the flow suppressing member; The molding cavity is filled with the sealing resin on the main surface side of the support plate and on the other main surface side, and the sealing resin is filled with the sealing resin, so that the electronic element, the flow suppressing member, the support plate, and the external lead are sealed. The present invention relates to a method of manufacturing a resin-sealed electronic component, characterized by comprising a fourth step of covering a portion of the electronic component with the sealing resin.

In addition, as shown in claim 2, it is desirable to provide a stepped portion within the molding cavity.

[For production]

According to the invention set forth in claim 1 of the present application, the flow suppressing member is
Since it is located closer to the resin injection port than the electronic element, the flow of the sealing resin injected from the resin injection port to one main surface of the support plate is prevented by this flow suppressing member (flow stopper member). Therefore, the flow of the sealing resin injected onto one main surface of the support plate is weakened, and the flow of the sealing resin injected onto the other main surface of the support plate is relatively reduced. As a result, the injection balance of the sealing resin injected into one main surface side of the support plate and the other main surface side of the support plate is improved, and the flow of the sealing resin injected into the other main surface side of the support plate is improved. A thin resin layer can be formed satisfactorily on the side.

The flow suppression effect can be adjusted by changing the size, mainly the height, of the flow suppression member. Therefore, by appropriately changing the size of the flow suppressing member, a wide variety of electronic components can be manufactured using the same mold. In addition, the flow suppressing member is formed separately from the lead frame, and can be formed without changing the shape of the lead frame. Therefore, the flow suppression effect can be adjusted without changing the shape of the lead frame, which is easy to handle.

Further, according to the invention described in claim 2 of the present application, the first part of the upper mold
Since the distance between the surface of the support plate and one main surface of the support plate is small, this part can suppress the flow of the sealing resin on the one main image side of the support plate, and furthermore, this flow can be suppressed. It can be suppressed again with a suppressing member. Therefore, a flow suppressing effect can be effectively obtained, and moldability is improved.

〔Example〕

A method of manufacturing a resin-sealed semiconductor device (transistor), which is an embodiment of the present invention, will be described below with reference to FIGS. 1 to 5.

To manufacture the semiconductor device of this embodiment shown in FIG. 5, first, the lead frame 1 shown in FIG. 5 is prepared. The lead frame 1 includes a support plate 2 made of a solderable metal plate, a plurality of external leads 3 arranged on one end side of the support plate 2, and a typer 4 that connects the plurality of external leads 5 in parallel. and a connecting strip 5, a supporting strip 6 connected to the other end of the support plate 2, and a connecting strip 7 connecting the supporting strip 6 in parallel. Reference numeral 8 denotes a hole passing through the support plate 2 in the thickness direction, into which a mounting screw, screw, etc. is inserted. The plurality of external leads 3 are composed of connected external leads 3a connected to one end of the support plate 2 and unconnected external leads 3b not connected to one end of the support plate 2. In addition, the strip 6 has a hole 9 penetrating through its thickness.
, and one small cross-section portion is formed on both sides of the hole 9. The strip 6 is thinner and thicker than the support plate 2, and is offset upwardly so that one main surface thereof is located substantially in the same plane as one main surface of the support plate 2.

Next, as shown in FIG. 4, solder (not shown) and adhesive (not shown) are applied to the semiconductor element 11 and the flow prevention member 12 on one main surface of the support plate 2, respectively. It is fixed through. A thin lead wire 1'5 is connected between an electrode (not shown) formed on the upper surface of the semiconductor element 11 and the unconnected external lead 3b. The flow suppressing member 12 is a rod-shaped metal body, and extends in the width direction of the support plate, that is, in the direction perpendicular to the extending direction of the external lead 3. In addition, the flow suppressing member 1
The second layer has a thickness greater than that of the semiconductor element 11.

The flow suppressing member 12 is disposed closer to the other end of the support plate 2 than the semiconductor element 11 is, and is located between the hole 8 and the semiconductor element 11 in a plan view and approximately in the center of the support plate 2. It is fixed. The function of this flow suppressing member 12 will be explained later. The lead frame 1 in which the semiconductor element 11, the flow suppressing member 12, and the thin lead wire 13 are formed is hereinafter referred to as a lead frame assembly 31.

Next, in order to form the resin stopper 14 shown in FIG. 5 on the lead frame assembly 31 by the well-known transfer molding method, the lead frame assembly 31 is placed in the mold 15 as shown in FIG. do.

The mold 15 is composed of an upper mold 16 and a lower mold 17. The clay mold 16 is formed with a recess 18 and a cylindrical projection 19, and the projection 19 is inserted into the hole 8 of the support plate 2.

However, since the convex portion 19 is spaced apart from the inner peripheral surface of the hole 8,
A portion of the resin barrier 14 is formed on the inner peripheral surface of the hole 8 .

The lower mold 17 has a recess 20 and a groove 21 for inserting the external lead B.
, launch (resin injection path) 22, gate (resin injection port) 2
3. A groove 24 is provided for the insertion of the support strip 6.

The molding die 15 is closed by closing the upper die 16 and the lower die 17.
A molding cavity 25 corresponding to the resin sealing body 14 in the recess 18 and the recess 2o is formed inside. Gaito lead 3 and support strips if: Shitetsu mold 16 and lower mold 17 that fit into grooves 21 and 24
held by. As a result, the support plate 2 is positioned floating in the molding cavity Pfr25 such that the distance between the other main surface and the bottom surface of the molding cavity 25 is about 0.5 mm. The distance between one main surface of the support plate 2 and the top surface of the molding space 25 is sufficiently larger than the distance between the other main surface of the support plate 2 and the bottom surface of the molding space PJT 25, as shown. A stepped portion 18a is formed in the recessed portion 18 of the upper mold 16. The support plate 2 has a first upper surface 18b on the side where the holes 8 are shaped, and has a second upper surface 18c'Y on the side of the support plate 2 on which the semiconductor elements 11 are placed. The first upper surface 18b also has a concave portion 2 on the second upper surface 18c.
The distance between one main surface of the support plate 2 and the first upper surface 18b of the molding cavity 25 is such that the distance between the one main surface of the support plate 2 and the second upper surface 18b of the molding cavity 25 is It is smaller than the distance from the upper surface 18c. The flow suppressing member 12 has a stepped portion 18a.
It is placed so that its end on the resin injection port 23 side is positioned below the boundary between the upper surface 18c and the second upper surface 18c.

Next, as shown in FIG. 2, a sealing resin 2 is placed in the molding cavity 25.
6, a sealing resin is poured into the pot of the molding die 15 and fluidized, and the resin is press-injected into the molding cavity 25 from the resin injection port 23.

The sealing resin 26 injected from the resin injection port 23 flows in a branched manner to both one main surface side and the other main surface side of the support plate 2, as shown by arrows in FIG. In this example,
Since the resin injection port 23 is positioned below one main surface of the support plate 2, the sealing resin 26 is relatively easily injected onto the other main surface of the support plate 2. The flow of the sealing resin 26 injected onto one raw surface of the support plate 2 is suppressed by the flow suppressing member 12 placed on one main surface of the support plate 2 . In non-embodiments, the first upper surface 18 of the clay mold 16
The flow of the sealing resin 26 is suppressed by the narrow gap between b and one main surface of the support plate 2, and the flow is suppressed again by the flow suppressing member 12, so that the flow of the sealing resin 26 of the support plate 2 is The flow toward one main surface can be effectively suppressed. Therefore, the flow of the sealing resin 26 on the other raw surface side of the support plate 2 can be relatively strengthened, and as a result, the sealing resin 26 can be applied to one main surface and the other main surface side of the support plate 2. The resin 26 can be injected in a well-balanced manner. In addition, since there is a convex portion 19 in the main flow direction of the sealing resin 26 when viewed from the resin injection port 23, this convex portion 19 also acts to suppress the flow of the sealing resin 26. Therefore, the resin injection port 23 of the protrusion 19 is located on the extension of the line connecting the resin injection port 23 and the convex portion 19.
An unfilled portion of the restraining resin 26 is likely to occur in the region on the opposite side. In this embodiment, the flow of the sealing resin 26 separated by the convex part 19 is suppressed again by the flow suppressing member 12, so that the sealing resin 26 in the area K opposite to the convex part 19 is easily rotated. This problem of underfilling is reliably prevented. Furthermore, the sealing resin 26 is relatively injected into the boundary between the stepped portion 18a and the second upper surface 18c, so that the VC
In the non-example, the feeding resin 26 is controlled by the flow suppressing member 12.
Since it is easy to turn into the second upper surface 18c side,
The sealing resin 26 is also satisfactorily filled in the boundary portion.

Once the sealing resin 26 in the molding cavity 7fr25 has hardened, the lead frame 1 is taken out from the bottom mold 15. The resin sealing body 14 in FIG. 5 formed by solidifying the sealing resin 26 is as follows:
It includes the semiconductor element 11 and the flow suppressing member 12, and covers the entire surface of the support plate 2, the support strip 6, and a part of the external lead 5. The tieper 4 and the connecting strip 5 are cut by a press die, and the supporting strip 6 is made into a hole 9 by applying a tensile force in the direction in which it is drawn out.
It is broken at the small cross-section portions 1o formed on the left and right sides. Since the small cross-section portion 10 is located inside the resin sealing body 14, according to this embodiment, the broken portion of the support strip 6 can be formed inside the resin sealing body 14. Therefore, the creepage distance between the broken part of the support strip 6 and the external heat sink can be made sufficiently large. Furthermore, the fact that the support strips 6 are offset toward the main surface of the support plate 2 is advantageous in that a large creepage distance can be obtained. Furthermore, since one main surface of the support strip 6 and one main surface of the support plate 2 are on the same plane, cranks or the like may not occur in the resin sealing body 14 around the support strip 6 due to pull-out stress. do not have. In the lead frame shown in the conventional example, which has a structure in which the tip of the support plate is bent, when the support strip is extended from the bent portion and the support strip is pulled out and broken, the bent portion is deflected due to the pulling stress. Crank may occur in the resin molded body. Therefore, it is difficult to pull out and break the support strips in this type of lead frame. Therefore, the supporting details? High-voltage ゛1''8 with the cut section located inside the resin sealing hole.
It is difficult to realize a conductor device.

FIG. 5 shows a resin molded semiconductor device manufactured in this example. 32 is a mounting hole, and 35 is a hole formed by pulling out the support strip 6.

[Modified example]

The present invention is not limited to the above-described embodiments, and the following modifications are possible, for example.

The size of the il+ flow suppressing member 12 should be set to an optimal size in consideration of the injection balance of the J-to-1 stopper resin and the volume occupied by the lead frame assembly hole 31 in the molding cavity 25. That is, if the flow of the sealing resin on one main surface of the support plate 2 is weaker than in the example, the height of the flow suppressing member 12 is made smaller than in the example, and if it is stronger than in the example. In this embodiment, the height of the flow suppression part 12 is increased. 1. Lead frame assembly rest 31 molding space 25
If the volume of i6 in Jt is the same, injection of the restraining resin f# can be made the same, so in FIG. It is preferable to reduce the volume of the flow suppressing member 12 by the volume increase. Further, the flow suppressing member 12 does not need to be prismatic, and may be cylindrical or semi-cylindrical.

+21 The step portion 18a may not be formed in the upper mold 16 of the molding die 15. However, in order to effectively suppress the flow of the sealing resin 26 on one main surface side of the support plate 2,
A stepped portion 18a is provided in the clay mold 16, and the injection force of the hooking resin 26 is weakened by a narrow interval between the first upper surface 18b of the lower mold 17 that is deviated toward the concave portion 20 side and one main surface of the support plate 2. Later, it is desirable to weaken the flow of the sealing resin 26 again using the flow suppressing member 12.

{31 The arrangement position of the flow suppression member 12 is if1 for suppression
Although this is not an arbitrary setting in order to adjust the injection balance of the fat 26, the position is further away from the resin injection port 23 than the convex part 19 so that the sealing resin 26 can easily be rolled into the area opposite the convex part 190. It is preferable to place it in

1. When the stepped portion 18a4 is provided, the flow suppressing member 12 is placed on the first upper surface 1 so that the sealing resin 26 is well filled in the boundary between the stepped portion 18a and the second upper surface 18c.
It is preferable to arrange it closer to the second upper surface 18c than the boundary between the stepped portion 8b and the stepped portion 18a. At this time, if the flow suppressing member 12 is placed approximately at the center of the support plate 2, the flow suppressing member 12K can effectively relieve stress caused by expansion, contraction, deformation, etc. of the resin sealing body 14. .

(4) A recessed portion may be formed in the center of the flow suppressing member 12. By forming the concave convex portion 19 on a straight line connecting the semiconductor element 11, the effect of suppressing the flow of the sealing resin 26 by the flow suppressing member 12 on the straight line can be reduced. Therefore, the effect of suppressing the sealing resin 26 by the convex portion 19 is offset, and the sealing resin 26 is easily injected into the region on the opposite side of the convex portion 19 . Cabinet,
It is also possible to reliably prevent the thin lead 1fM13 from hanging down due to the rotation of the anchoring resin 26.

(5; It is desirable that the flow suppressing member 12 extends over half or more of the width of the support plate 2 in order to obtain a sufficient flow suppressing effect. In order to sufficiently enhance the above effect, it is desirable that the flow suppressing member 12 extends over half or more of the width of the support plate 2. It is best to extend it over the entire length.

(6) The flow suppressing member 12 may be formed from a material other than metal.

(7) In the case of the embodiment, the part where the support strip 6 is broken is not covered with the resin patch 14, but this part may be covered with another resin. Moreover, it can be applied even when one support string 6 is not provided. Furthermore, the present invention can also be applied to a case where a part of the support plate 2 is not covered with the resin stopper body 14 for some reason.

(8) It can also be applied to electronic components in which a circuit board or the like is fixed to one main surface of the support plate 2. Furthermore, the electronic element referred to in the present invention includes an electronic element formed by printing a thick film conductive paste or the like on a circuit board.

(9) The semiconductor element 11 and the flow suppression portion shrine 12 are connected to the support plate 2.
They may be fixed at the same time, or one of them may be fixed first.

(IO) In the state shown in Fig. 6, sealing resin is molded into the cavity 25.
can be injected into. Since many parts of FIG. 6 are the same as FIG. 1, the same parts as in FIG. 1 are given the same reference numerals and their explanations will be omitted. In the example in Figure 6,
The flow suppressing member 12 placed on one main surface of the support plate 2 is made of the same epoxy resin as the resin sealing body 14, and has a pair of protrusions 12a and 12b as shown in FIG. are doing. In addition, a flow suppressing member 1 is provided on the other main surface of the support plate 2.
A positioning member 34 made of an insulating material as shown in FIG. 8 is placed on the opposite side of the positioning member 2 . The height from the lower surface of the flow suppressing member 12 to the upper surface of the protrusions 12a, 12b is set to the distance between one main surface of the support plate 2 and the second upper surface 18c of the molding cavity 25, and the height of the positioning member 3
The thickness of 4 is set to the distance between the other main surface of the support plate 2 and the bottom surface of the molding cavity 25. Further, the width of the positioning material 34 is smaller than the width of the support plate 2. The upper mold 16 and the lower mold l flow through the support plate 2 via the suppressing member 12 and the positioning member 34.
7, the support plate 2 is positioned at a distance corresponding to the thickness of the positioning member 34 from the bottom surface of the oval cavity 25. That is, in the example shown in FIG. 6, the flow suppressing member 12 also functions as a positioning member. Also,
On the extension of the line connecting the resin injection port 23 and the protrusion 19, a pair of protrusions 12 are provided in the area opposite to the resin injection port 23 of one protrusion.
The flow suppressing member 12 is arranged so that the recess 12c between the flow suppressing member 12a and the recess 12c is located between the flow suppressing member 12a and the recess 12c. Therefore, the sealing resin 26 easily wraps around the region on the opposite side of one of the convex portions. The flow suppressing member l2 and the positioning member 34 become part of an envelope that closely contacts the resin sealing body 14 and covers the support plate 2. In this example, the support strips 6 shown in FIG. 1 are not required, and the entire surface of the support plate 2 can be covered with an envelope. Note that since the step portion is formed on the bottom surface of the positioning member 34, the creeping distance between the other main surface of the support plate along the interface between the positioning member 34 and the resin sealing body 14 and the external heat radiator can be increased.

(l1) The plurality of protrusions 12a and l2b in FIG. 7 can be replaced with one protrusion. Furthermore, instead of providing the protruding portion on the flow suppressing member 12, a protruding portion or a pin may be provided on the upper mold 16, and the flow suppressing member 12 may be held down with this.

[Effects of the Invention] As described above, according to the present invention, it is possible to manufacture a resin-sealed electronic component with good moldability in which a portion of the resin seal is also formed on the back side of the support plate. In addition, a wide variety of electronic components can be manufactured using the same mold, making it possible to produce a wide variety of products at low cost.

[Brief explanation of drawings]

FIG. 1 shows a state in which a lead frame assembly is placed in a cutting die in order to manufacture a resin-sealed semiconductor device according to an embodiment of the present invention, in a portion corresponding to line I-1 in FIG. 3. 2 is a sectional view showing the state in which the sealing resin is injected into the mold shown in FIG. 1, FIG. 3 is a plan view showing the lead frame, and FIG. 3. FIG. 5 is a perspective view showing a completed resin-sealed semiconductor device. FIG. 6 shows a modification of the present invention corresponding to FIG. 1. 7 is an enlarged perspective view of the flow suppressing member shown in FIG. 6; and FIG. 8 is an enlarged perspective view showing the positioning member shown in FIG. 6. 1... Lead frame, 2... Support plate, 12...
Flow suppressing member, 15...Mold, 16...Upper mold, 17
...lower mold, 25...molding cavity.

Claims (1)

[Scope of Claims] [1] A first step of preparing a lead frame having a support plate and an external lead connected to one end of the support plate; and one of the support plates of the lead frame. An electronic element is fixed to the main surface, and a longitudinal flow suppressing member extending in a direction perpendicular to the extending direction of the external lead is connected between the fixed position of the electronic element and the other end of the support plate. a second step of obtaining a lead frame assembly by fixing the gap between the other main surface of the support plate and the bottom surface of the molding cavity such that the distance between the one main surface of the support plate and the top surface of the molding cavity is a third step of arranging the lead frame assembly in a molding die such that the gap is smaller than the distance between the lead frame assembly and the resin injection port disposed on the other end side of the support plate in the molding cavity; A sealing resin is injected into the molding cavity, and the molding is performed while suppressing the flow of the sealing resin injected onto one main surface side of the support plate in the molding cavity with the flow suppressing member. The sealing resin is filled in one main surface side and the other main surface side of the supporting plate in the empty space, and the electronic element, the flow suppressing member, the supporting plate, and a part of the external lead are sealed. a fourth step of coating the resin with the sealing resin. [2] A first step of preparing a lead frame having a support plate and an external lead connected to one end of the support plate, and providing an electronic element on one main surface of the support plate of the lead frame. At the same time, a longitudinal flow suppressing member extending in a direction perpendicular to the extending direction of the external lead is fixed between the fixing position of the electronic element and the other end of the support plate. a second step of obtaining a frame assembly, comprising an upper mold and a lower mold each having a recess for forming a molding cavity, the recess of the upper mold being in the planned placement plane of the upper surface of the support plate; a first interval having a first interval with respect to
and a second surface having a second distance wider than the first distance with respect to the planned placement plane, and a stepped portion between the first and second surfaces. , the first surface is provided on the side where the other end of the support plate is arranged, the second surface is provided on the side where the one end of the support plate is arranged, and the molding a fifth step of preparing a molding mold in which the resin injection port leading to the cavity is provided on the side where the other end of the support plate is arranged, and the resin injection port corresponds to the planned placement plane in the molding cavity; a fourth step of arranging the lead frame assembly in the molding die such that the support plate is positioned as such and the flow suppressing member faces the stepped portion and/or the second surface; A sealing resin is injected into the molding cavity from the resin injection port, and the flow of the sealing resin injected into one main surface side of the support plate of the molding cavity is directed to the first surface and the molding cavity. While suppressing the flow with the flow suppressing member, each of the front main surface sides is filled with the sealing resin, and the electronic element, the flow suppressing member, the support plate, and a part of the external lead are sealed together with the sealing resin. A method for manufacturing a resin-sealed electronic component, comprising a fifth step of coating with a resin.